A woman throws an object of mass 500 g with a speed of 25 m/s

A woman throws an object of mass 500 g with a speed of 25 m/s.
(i) What is the impulse imparted to the object?
(ii) If the object hits a wall and rebounds with half
the original speed, what is the change in momentum of the object?

Mass of the object (m) = 500g = 0.5 kg
Speed of the object (v) = 25 m/s
(i) Impulse imparted to the object = Change in the momentum = mv-mu
= m(v-u)
= 0.5(25-0) = 12.5 N-s
(ii) Velocity of the object after rebounding = -25/2 m/s
v’ = -12.5 m/s

Change in momentum = m(v’ - v)
= 0.5 (-12.5 -25)
= -18.75 N-s